Patients with HIV have a deficiency of CD4 lymphocytes which are also known as helper T cells (Th). They are involved with antigen-specific responses as well as delayed-type hypersensitivity. The risk of developing P. jiroveci pneumonia is greatest with a CD4 count of 200 x 109/l or below.

Recommended regimens3 NRTI (e.g., zidovudine, lamivudine, abacavir) OR2 NRTI (e.g., lamivudine + abacavir) AND1 NNRTI (e.g., efavirenz) OR1 PI (e.g., lopinavir) OR1 INI (e.g., raltegravir)

The most appropriate action in this baby would be to perform HIV PCR and commence cART and PCP prophylaxis if HIV positive.Treatment guidelines for HIV-positive infants state that all should receive combination antiretroviral therapy (cART) and Pneumocystis jiroveci pneumonia (PJP) prophylaxis, irrespective of CD4 count or viral load.

Unprotected anal or vaginal sexual intercourse with an infected individual is by far the most common (95%) route by which HIV is transmitted. Other options:- Blood transfusion is an extremely rare cause of HIV transmission in the UK. – While HIV can be transmitted from mother to baby either during birth or via breastfeeding, the transmission rate is only 5 – 20%.- Sharing contaminated needles does put individuals at risk of getting HIV, although public health measures are in place to reduce this risk. – Although HIV can be transmitted via this route, it is around ten times less likely to result in transmission than unprotected anal or vaginal intercourse with an infected individual.

The antiretroviral agent for the side effects mentioned is most probably, efavirenz.Efavirenz is a non-nucleoside reverse transcriptase inhibitor and the most likely cause of new-onset psychiatric symptoms in someone taking HAART. In this scenario the patient had no pre-existing mental health problems, as other antiretrovirals can cause depression and suicidal ideation in those who have a past psychiatric history. Symptoms usually subside after a few weeks of treatment.Other options:- Emtricitabine is a nucleoside reverse transcriptase inhibitor and is also not known to cause psychiatric side effects. The most common side effects of Emtricitabine are rash and darkening of the palms or soles.- Lamivudine is a nucleoside reverse transcriptase inhibitor, which can cause insomnia, but does not commonly cause other psychiatric symptoms.- Rilpivirine is a non-nucleoside reverse transcriptase inhibitor, which can cause depression. However, this is more common in those with a history of mental health problems.- Tenofovir is a nucleotide reverse transcriptase inhibitor. The most common side effect of Tenofovir is gastrointestinal upset. It is not known to cause psychiatric side effects.

Live attenuated vaccines such as the MMR, should be avoided in HIV+ patients.

Among the options provided, zidovudine causes lipoatrophy as a side effect.Zidovudine: Although both hypertrophy and atrophy are described related to HIV medications, nucleoside reverse transcriptase inhibitor (NRTIs) such as zidovudine and stavudine are closely associated with fat loss.Other options:- Enfuvirtide is an HIV-fusion inhibitor. Lipoatrophy is not commonly associated with this drug.- Efavirenz is an NNRTI, which is not associated with lipoatrophy. Common side effects include neuropsychiatric effects, rash and nausea. – Ganciclovir is not an anti-HIV medication and is used for cytomegalovirus (CMV) infections.- Raltegravir is an integrase inhibitor and is associated with fat gain.

According to the Rumack-Matthew Normogram, accurate levels of paracetamol can be measured only between 4-15 hours. The levels measured before 4 hours post-ingestion would highly underestimate the level of paracetamol ingested.The patient in question presents 2 hours after ingestion. Hence the most appropriate time to measure the levels of acetaminophen would be a further 2 hours later. Other options:- Note that the treatment with NAC can be delayed until the 4-hour level is obtained and compared to the nomogram.- Furthermore, haemodialysis is only indicated if she develops hepato-renal syndrome that is likely to occur 72-96 hours post-ingestion.- Indications for acute liver transplantation include persistent acidosis, hepatorenal syndrome and worsening coagulopathy.

Based on the presentation, she probably was administered co-amoxiclav.The liver function tests are highly suggestive of cholestatic jaundice, which is a classic adverse dug reaction related to co-amoxiclav use.Other options:- Erythromycin is more commonly associated with gastrointestinal (GI) disturbance.- Gentamicin is more commonly associated with renal impairment.- Meropenem does not commonly cause cholestasis but is associated with transaminitis.- Vancomycin is associated with red man syndrome on fast administration.

Infants exposed to maternal HIV and with positive results require immediate management with co-trimoxazole prophylaxis, regardless of their CD4 levels. Antiretroviral treatment is necessary as well but it could wait until further work-up is complete.